Step-by-step explanation:
4 + n + 7m
constants are just the numbers with no variables (letters)
so the constant is 4
coefficients are numbers multiplied by variables (letters)
so the coefficients are : 7 and 1
the error sarah made is forgetting the coefficient of n......because even if it is not written, n is the same as 1n....so basically, there is a coefficient for EVERY variable, even if its not written.